The SWOG Statistical Center in Seattle served as the coordinating center for two large prostate cancer prevention trials, the Selenium and Vitamin E Cancer Prevention Trial (SELECT) and the Prostate Cancer Prevention Trial (PCPT). SELECT was a Phase III, double-blind, placebo-controlled study designed to assess the effect of selenium and vitamin E, alone and in combination, on prostate cancer incidence. SELECT randomized 35,533 men between 2001-2004. PCPT, also a Phase III, double-blind trial, randomized 18,882 men to either finasteride or placebo between 1994-1997. Although schedules and requirements varied between the two, substantial serum, plasma, white blood cells and prostate tissue were collected on both, resulting in rich biorepositories. Each had extensive prospective data collections which included diet and supplements, quality of life, physical activity, medications, other cancer diagnoses, cardiovascular endpoints, and treatment adverse events. Although there have been significant scientific collaborations to date, there remain numerous opportunities to further interrogate the clinical database and biobanks. additionally, a number of serum and plasma measures and genotyping data have already been obtained and are available for other investigators to use. Now that the clinical trial portion is completed, these cohorts can be used for epidemiologic research. Also, SELECT continues to actively follow a subset of men who can be contacted for additional data. We request funds to provide a stable infrastructure to support the serum repository for PCPT and tissue repository for PCPT and SELECT (all located at the University of Colorado) and to support the ongoing data analysis applications from both trials. We will continue our efforts to obtain prostate tissue from men diagnosed with prostate cancer on SELECT, and we will obtain cause of death information from a National Death Index search. By continuing to fund the Statistical Center team and some of our key scientific colleagues, we are able to help investigators apply for additional funding to conduct studies using our rich biologic repositories and clinical databases from PCPT and SELECT. RELEVANCE: By fully using the data and biologic samples from these large cohorts with extensive follow-up, we will be able to evaluate risk factors for prostate cancer, and subsequent prognosis. We will be able to contribute clinical and demographic data and biologic samples for men diagnosed with other cancers to researchers to better understand the etiology of those cancers.